Developer documentation of the functions and datastructures used for deserializing MQTT control packets. More...

Data Structures
struct	mqtt_fixed_header
	The fixed header of an MQTT control packet. More...

struct	mqtt_response_connack
	A connection response datastructure. More...

struct	mqtt_response_publish
	A publish packet received from the broker.A publish packet is received from the broker when a client publishes to a topic that the {local client} is subscribed to. More...

struct	mqtt_response_puback
	A publish acknowledgement for messages that were published with QoS level 1. More...

struct	mqtt_response_pubrec
	The response packet to a PUBLISH packet with QoS level 2. More...

struct	mqtt_response_pubrel
	The response to a PUBREC packet. More...

struct	mqtt_response_pubcomp
	The response to a PUBREL packet. More...

struct	mqtt_response_suback
	The response to a subscription request. More...

struct	mqtt_response_unsuback
	The brokers response to a UNSUBSCRIBE request. More...

struct	mqtt_response_pingresp
	The response to a ping request. More...

struct	mqtt_response
	A struct used to deserialize/interpret an incoming packet from the broker. More...

Enumerations
enum	MQTTControlPacketType { MQTT_CONTROL_CONNECT =1u, MQTT_CONTROL_CONNACK =2u, MQTT_CONTROL_PUBLISH =3u, MQTT_CONTROL_PUBACK =4u, MQTT_CONTROL_PUBREC =5u, MQTT_CONTROL_PUBREL =6u, MQTT_CONTROL_PUBCOMP =7u, MQTT_CONTROL_SUBSCRIBE =8u, MQTT_CONTROL_SUBACK =9u, MQTT_CONTROL_UNSUBSCRIBE =10u, MQTT_CONTROL_UNSUBACK =11u, MQTT_CONTROL_PINGREQ =12u, MQTT_CONTROL_PINGRESP =13u, MQTT_CONTROL_DISCONNECT =14u }
	An enumeration of the MQTT control packet types. More...

enum	MQTTConnackReturnCode { MQTT_CONNACK_ACCEPTED = 0u, MQTT_CONNACK_REFUSED_PROTOCOL_VERSION = 1u, MQTT_CONNACK_REFUSED_IDENTIFIER_REJECTED = 2u, MQTT_CONNACK_REFUSED_SERVER_UNAVAILABLE = 3u, MQTT_CONNACK_REFUSED_BAD_USER_NAME_OR_PASSWORD = 4u, MQTT_CONNACK_REFUSED_NOT_AUTHORIZED = 5u }
	An enumeration of the return codes returned in a CONNACK packet. More...

enum	MQTTSubackReturnCodes { MQTT_SUBACK_SUCCESS_MAX_QOS_0 = 0u, MQTT_SUBACK_SUCCESS_MAX_QOS_1 = 1u, MQTT_SUBACK_SUCCESS_MAX_QOS_2 = 2u, MQTT_SUBACK_FAILURE = 128u }
	An enumeration of subscription acknowledgement return codes. More...

Functions
ssize_t	mqtt_unpack_fixed_header (struct mqtt_response response, const uint8_t buf, size_t bufsz)
	Deserialize the contents of `buf` into an mqtt_fixed_header object. More...

ssize_t	mqtt_unpack_connack_response (struct mqtt_response mqtt_response, const uint8_t buf)
	Deserialize a CONNACK response from `buf`. More...

ssize_t	mqtt_unpack_publish_response (struct mqtt_response mqtt_response, const uint8_t buf)
	Deserialize a publish response from `buf`. More...

ssize_t	mqtt_unpack_pubxxx_response (struct mqtt_response mqtt_response, const uint8_t buf)
	Deserialize a PUBACK/PUBREC/PUBREL/PUBCOMP packet from `buf`. More...

ssize_t	mqtt_unpack_response (struct mqtt_response response, const uint8_t buf, size_t bufsz)
	Deserialize a packet from the broker. More...

Detailed Description

Developer documentation of the functions and datastructures used for deserializing MQTT control packets.

Enumeration Type Documentation

◆ MQTTConnackReturnCode

enum MQTTConnackReturnCode

An enumeration of the return codes returned in a CONNACK packet.

See also: MQTT v3.1.1: CONNACK return codes.

◆ MQTTControlPacketType

enum MQTTControlPacketType

An enumeration of the MQTT control packet types.

See also: MQTT v3.1.1: MQTT Control Packet Types

◆ MQTTSubackReturnCodes

enum MQTTSubackReturnCodes

An enumeration of subscription acknowledgement return codes.

See also: MQTT v3.1.1: SUBACK Return Codes.

Function Documentation

◆ mqtt_unpack_connack_response()

ssize_t mqtt_unpack_connack_response	(	struct mqtt_response *	mqtt_response,
		const uint8_t *	buf
	)

Precondition: mqtt_unpack_fixed_header must have returned a positive value and the control packet type must be MQTT_CONTROL_CONNACK.

Parameters

[out]	mqtt_response	the mqtt_response that will be initialized.
[in]	buf	the buffer that contains the variable header and payload of the packet. The first byte of `buf` should be the first byte of the variable header.

Returns: The number of bytes that were consumed, or 0 if the buffer does not contain enough bytes to parse the packet, or a negative value if there was a protocol violation.

◆ mqtt_unpack_fixed_header()

ssize_t mqtt_unpack_fixed_header	(	struct mqtt_response *	response,
		const uint8_t *	buf,
		size_t	bufsz
	)

Deserialize the contents of buf into an mqtt_fixed_header object.

Note: This function performs complete error checking and a positive return value means the entire mqtt_response can be deserialized from buf.

Parameters

[out]	response	the response who's mqtt_response::fixed_header will be initialized.
[in]	buf	the buffer.
[in]	bufsz	the total number of bytes in the buffer.

Returns: The number of bytes that were consumed, or 0 if the buffer does not contain enough bytes to parse the packet, or a negative value if there was a protocol violation.

◆ mqtt_unpack_publish_response()

ssize_t mqtt_unpack_publish_response	(	struct mqtt_response *	mqtt_response,
		const uint8_t *	buf
	)

Precondition: mqtt_unpack_fixed_header must have returned a positive value and the mqtt_response must have a control type of MQTT_CONTROL_PUBLISH.

Parameters

[out]	mqtt_response	the response that is initialized from the contents of `buf`.
[in]	buf	the buffer with the incoming data.

Returns: The number of bytes that were consumed, or 0 if the buffer does not contain enough bytes to parse the packet, or a negative value if there was a protocol violation.

◆ mqtt_unpack_pubxxx_response()

ssize_t mqtt_unpack_pubxxx_response	(	struct mqtt_response *	mqtt_response,
		const uint8_t *	buf
	)

Precondition: mqtt_unpack_fixed_header must have returned a positive value and the mqtt_response must have a control type of MQTT_CONTROL_PUBACK, MQTT_CONTROL_PUBREC, MQTT_CONTROL_PUBREL or MQTT_CONTROL_PUBCOMP.

Parameters

[out]	mqtt_response	the response that is initialized from the contents of `buf`.
[in]	buf	the buffer with the incoming data.

mqtt_response_pubrec mqtt_response_pubrel mqtt_response_pubcomp

Returns: The number of bytes that were consumed, or 0 if the buffer does not contain enough bytes to parse the packet, or a negative value if there was a protocol violation.

◆ mqtt_unpack_response()

ssize_t mqtt_unpack_response	(	struct mqtt_response *	response,
		const uint8_t *	buf,
		size_t	bufsz
	)

Parameters

[out]	response	the mqtt_response that will be initialize from `buf`.
[in]	buf	the incoming data buffer.
[in]	bufsz	the number of bytes available in the buffer.

Returns: The number of bytes consumed on success, zero buf does not contain enough bytes to deserialize the packet, a negative value if a protocol violation was encountered.

Data Structures

Enumerations

Functions

Detailed Description

Enumeration Type Documentation

◆ MQTTConnackReturnCode

◆ MQTTControlPacketType

◆ MQTTSubackReturnCodes

Function Documentation

◆ mqtt_unpack_connack_response()

◆ mqtt_unpack_fixed_header()

◆ mqtt_unpack_publish_response()

◆ mqtt_unpack_pubxxx_response()

◆ mqtt_unpack_response()